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DS90UB935-Q1: 15m coaxial cable in 935/936 condition

Roy Chou1
Genius 16210 points
Part Number: DS90UB935-Q1

Hi team,

Since we only guarantees 15m coaxial cable in 935/936 operation. May I know if it all depends on margin analysis results and BIST error count? Should we also consider the group delay and phase delay caused by length and the material of coaxial cable? Or, margin analysis’s strobe position has already considered group delay and phase delay? Thank you.

Regards,

Roy

  • 0
    TI__Guru** 103215 points

    Roy,

    15m cable assumes that the total system design including cable type, PCB design, connectors, etc. are meeting the channel specifications for insertion loss, return loss, and TDR. The 15m is based on an assumption of high quality low loss cable such as Dacar 302. If the system design is fully meeting the channel specifications and the rest of the system design such as power supply stability is meeting the recommended operating conditions from the datasheets then the link should operate error free both in BIST and normal modes. The MAP can additionally be used to verify how much margin is seen in a particular system to system link but should not be used to substitute proper validation of the system s-parameters against the FPD channel specifications. 

    MAP is taken by real sampling of the data stream - not estimation of the margin by looking at some other figure of merit for the signal integrity. The MAP sweeps strobe position and EQ, then checks the received data pattern against a known pattern to see if the data is received properly at each square. So this is taking into account all channel effects seen between SER/DES as it is running. 

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Genius 16210 points

    Hi Casey,

    Thanks for comments.

    Really appreciate to your reply. May I have the specification of cable like return loss/insertion loss suggested by your side?

    Or you can send me via email.

    Regards,

    Roy

  • 0 in reply to Roy Chou1
    TI__Guru** 103215 points

    Hello Roy,

    This is located in the channel specifications folder inside CDDS. Please download from there so you always have the latest copy 

    Best Regards,

    Casey 

  • 0 in reply to Casey McCrea
    TI__Genius 16210 points

    Hi Casey,

    Can you let me know the key word that search in CDDS system?

    Roy

  • +1 in reply to Roy Chou1
    TI__Guru** 103215 points

    Hello Roy,

    It is in the folder called FPD-Link_Channel_Specs, see here: https://cdds.ext.ti.com/ematrix/common/emxTree.jsp?objectId=28670.42872.10174.37927&fromContent=true 

    If you do not have access please email the marketing team internally (Chanakya or Anwar) for support on getting access

    Best Regards,

    Casey